JP7424146B2 - Cap device and liquid discharge device - Google Patents

Description

The present invention relates to a cap device including a cap that covers a nozzle surface in which a plurality of nozzles are formed and a conductive housing member housed within the cap, and a liquid ejecting device including the cap device.

Patent Document 1 discloses that an ink absorbing member and a mesh electrode arranged on the surface of the ink absorbing member are housed in a box member (cap), and ink is ejected from a nozzle of a print head toward the electrode. It is indicated to perform a state check.

Japanese Patent Application Publication No. 2007-176152

In Patent Document 1, an ink absorbing member and an electrode are passed through a support rod integrally formed on the bottom surface of a box member, and the head of the support rod is heated and pressurized to caulk the head. The electrode (accommodating member) is fixed to the box member (cap). In this case, the head (convex part) of the support rod does not function as an electrode, so even if ink is ejected from the nozzle toward the head, the ejection state of the nozzle cannot be inspected, and the inspection accuracy may deteriorate. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a cap device and a liquid ejecting device that can suppress the problem that the accuracy of testing the ejection state deteriorates due to the convex portion.

A cap device according to the present invention includes a cap for covering a nozzle surface of a liquid ejection head having a nozzle surface formed with a plurality of nozzles for ejecting liquid onto a medium to be ejected, and a cap configured to face the nozzle surface. a conductive housing member housed in the housing member that is capable of generating a potential difference with the liquid ejection head; and a housing member that is electrically conductive when the housing member and the nozzle surface face each other a fixing part having a convex part extending through the housing member so as to protrude from the nozzle surface side surface of the housing member and fixing the housing member to the cap; The present invention is characterized by comprising a conductive cover having a surface along the nozzle surface side and capable of generating a potential difference between the cover and the liquid ejection head.

A liquid ejection device according to the present invention includes a liquid ejection head having a nozzle surface on which a plurality of nozzles are formed for ejecting liquid onto a medium to be ejected, a cap for covering the nozzle surface, and a cap capable of facing the nozzle surface. a conductive housing member housed in the cap and capable of generating a potential difference between the housing member and the liquid ejection head; a fixing part that has a convex part that penetrates the housing member so as to protrude from the surface of the housing member on the nozzle surface side and fixes the housing member to the cap; and a fixing part that covers the convex part and that covers the housing member. an electrically conductive cover having a surface along the nozzle surface side and capable of generating a potential difference between the liquid ejection head, the liquid ejection head, the housing member, and the liquid ejection head; A signal output unit that outputs a signal indicating a potential difference with the cover, and a control unit, the control unit discharging liquid from the plurality of nozzles toward the housing member and the cover, and outputting the signal. The present invention is characterized in that the discharge state of the plurality of nozzles is inspected based on the signal output from the output section.

According to the present invention, by providing the conductive cover that covers the convex portion and has a surface along the nozzle surface side of the housing member, the problem of deterioration of the inspection accuracy of the discharge state due to the convex portion is suppressed. can.

1 is a plan view of a printer according to an embodiment of the present invention. 2 is a sectional view of a head included in the printer of FIG. 1. FIG. 2 is a plan view of a cap device included in the printer of FIG. 1. FIG. FIG. 4 is a cross-sectional view of the cap device taken along line IV-IV in FIG. 3; 5 is an enlarged view of a region V surrounded by a dashed line in FIG. 4. FIG. FIG. 2 is a block diagram showing the electrical configuration of the printer in FIG. 1. FIG. (a) is a diagram showing changes in voltage of the housing member and the cover when ink is ejected from the nozzle. (b) is a diagram showing changes in the voltages of the housing member and the cover when ink is not ejected from the nozzle. FIG. 8 is a diagram corresponding to FIG. 7 in another embodiment of the invention. FIG. 5 is a diagram corresponding to FIG. 4 in a modified example of the present invention.

As shown in FIG. 1, a printer 100 according to an embodiment of the present invention includes a head 1, a carriage 2, a platen 3, a transport mechanism 4, a maintenance unit 5 including a cap device 51, and a control device 9. It is equipped with The printer 100 corresponds to the "liquid ejection apparatus" of the invention, and the head 1 corresponds to the "liquid ejection head" of the invention.

The head 1 includes a flow path unit 11 and an actuator unit 12, as shown in FIG. The lower surface of the channel unit 11 is a nozzle surface 11a on which a plurality of nozzles 11n are formed, and is perpendicular to the vertical direction. A common channel 11x communicating with an ink tank (not shown) and a plurality of individual channels 11y extending from the common channel 11x to each of the plurality of nozzles 11n are formed inside the channel unit 11. A plurality of pressure chambers 11c included in each of the plurality of individual flow paths 11y are open on the upper surface of the flow path unit 11. The actuator unit 12 includes a diaphragm 121 arranged on the upper surface of the flow path unit 11 so as to cover the plurality of pressure chambers 11c, a piezoelectric layer 122 arranged on the upper surface of the diaphragm 121, and a plurality of diaphragms on the upper surface of the piezoelectric layer 122. and a plurality of individual electrodes 123 arranged to face each of the pressure chambers 11c. The portion of the diaphragm 121 and the piezoelectric layer 122 sandwiched between each individual electrode 123 and each pressure chamber 11c functions as an individual unimorph type actuator for each pressure chamber 11c, and the voltage applied to each individual electrode 123 by the driver IC 15 is controlled. It can be deformed independently depending on the application. By deforming the actuator so as to be convex toward the pressure chamber 11c, the volume of the pressure chamber 11c is reduced, pressure is applied to the ink within the pressure chamber 11c, and the ink is ejected from the nozzle 11n.

As shown in FIG. 1, the carriage 2 holds the head 1 and is supported by two guide rails 21 and 22 along the scanning direction parallel to the nozzle surface 11a. When the carriage motor 25 (see FIG. 6) is driven under the control of the control device 9, the carriage 2 moves in the scanning direction along the guide rails 2a and 2b. Thereby, the head 1 can take a maintenance position where it faces the cap device 51 in the vertical direction, and a non-maintenance position where it does not face the cap device 51 in the vertical direction.

The platen 3 is arranged below the head 1 and carriage 2. A paper P is supported on the upper surface of the platen 3. The paper P corresponds to the "ejected medium" of the present invention.

The conveyance mechanism 4 includes two roller pairs 41 and 42 arranged with the platen 3 in between in the conveyance direction. The transport direction is parallel to the nozzle surface 11a and perpendicular to the scanning direction. When the transport motor 45 (see FIG. 6) is driven under the control of the control device 9, the pair of rollers 41 and 42 rotates while holding the paper P between them, and the paper P is transported in the transport direction.

The maintenance unit 5 includes a cap device 51, a suction pump 56, and a waste liquid tank 57. The cap device 51 is disposed on one side of the platen 3 in the scanning direction.

As shown in FIGS. 3 and 4, the cap device 51 includes a cap 511, a housing member 512 housed in the cap 511, and a cover 513 fitted in a recess 512b provided at the center of the housing member 512. A cap holder 514 that supports the cap 511 is included.

The housing member 512 and the cover 513 function as electrodes for testing, which will be described later, and are electrically conductive, and in this embodiment are made of electrically conductive resin (such as POM (polyacetal) containing carbon powder).

Cap 511 and cap holder 514 are non-conductive. In this embodiment, the cap 511 is made of an elastic material such as rubber, and the cap holder 514 is made of a non-conductive synthetic resin or the like.

As shown in FIG. 4, the cap holder 514 includes a bottom portion 514a that is perpendicular to the vertical direction, and a side portion 514b that projects upward from the outer periphery of the bottom portion 514a. The cap 511 is arranged in a rectangular parallelepiped space defined by the bottom portion 514a and the side portions 514b.

Like the cap holder 514, the cap 511 includes a bottom portion 511a that is perpendicular to the vertical direction, and a side portion 511b that projects upward from the outer periphery of the bottom portion 511a. The housing member 512 is housed in a rectangular parallelepiped-shaped space defined by the bottom portion 511a and the side portions 511b. The housing member 512 has higher rigidity than the cap 511, and has a function of suppressing the side portion 511b from falling inward.

The housing member 512 has a surface 512a located on the outside of the recess 512b, and a surface 512c that is the bottom surface of the recess 512b. Both surfaces 512a and 512c face upward, and vertically face the nozzle surface 11a when the head 1 is in the maintenance position. The surface 512a is above the surface 512c, and when the head 1 is in the maintenance position, the vertical distance between the nozzle surface 11a and the surface 512a is smaller than the vertical distance between the nozzle surface 11a and the surface 512c.

Cap holder 514 further includes a convex portion 514p and a tube portion 514t.

The convex portion 514p protrudes upward from approximately the center of the bottom portion 514a in the conveying direction and the scanning direction, and passes through the bottom portion 511a of the cap 511 and the housing member 512. The convex portion 514p penetrates the housing member 512 so as to protrude from the surface 512c of the housing member 512, and its tip is disposed in the concave portion 512b. By fitting the retaining ring 515 into the recess 514x formed near the tip of the convex portion 514p, the housing member 512 is fixed to the cap 511, and the cap 511 and the housing member 512 are fixed to the cap holder 514. Ru. The convex portion 514p and the retaining ring 515 correspond to the “fixing portion” of the present invention.

Like the cap holder 514, the retaining ring 515 is non-conductive and is made of non-conductive synthetic resin or the like.

The tube portion 514t is provided at the center of the bottom portion 514a in the scanning direction and on the downstream side in the conveyance direction, and passes through the bottom portion 511a of the cap 511. The pipe portion 514t is formed with a discharge hole 519 that passes through the pipe portion 514t in the vertical direction. The discharge hole 519 is a hole for discharging ink within the cap 511, and communicates with the suction pump 56 via a tube. The discharge hole 519 is covered by the housing member 512.

The cover 513 covers the convex portion 514p and has a surface 513a along the surface 512a of the housing member 512. In this embodiment, the surface 513a is at the same height as the surface 512a, and when the head 1 is in the maintenance position, the vertical distance G between the nozzle surface 11a and the surface 512a and the vertical distance between the nozzle surface 11a and the surface 513a are The directional distances G are the same.

The housing member 512 has a pair of depressions 512d communicating with the depression 512b. The pair of depressions 512d extends from each of the two sides of the recess 512b along the scanning direction in a plan view (FIG. 3) toward the outside of the recess 512b in a direction parallel to the transport direction (first direction). (See Figure 4).

As shown in FIG. 3, the length of the cover 513 in the first direction is longer than the length in the second direction (the scanning direction, the direction perpendicular to the first direction and along the surface 512c). Hooks 513f that are inserted into the recesses 512d are provided at both ends of the cover 513 in the first direction (see FIGS. 3 and 4). The cover 513 is fixed to the housing member 512 by a hook 513f hooked onto a portion of the housing member 512 that defines the recess 512d.

As shown in FIG. 3, gaps Sa and Sb are provided between the surface 512a of the housing member 512 and the surface 513a of the cover 513. The gap Sa extends along each of two sides along the second direction (predetermined direction) of the outer edge of the surface 513a. The gap Sb extends along each of two sides of the outer edge of the surface 513a along the first direction (orthogonal direction). In other words, gaps Sa and Sb are provided all around the outer edge of the surface 513a.

The width Wa of the gap Sa in the first direction (orthogonal direction) is larger than the center-to-center distance D of the nozzles 11n in the orthogonal direction (see FIG. 1). The width Wb of the gap Sb in the second direction (predetermined direction) is the same as the width Wa. For example, the widths Wa and Wb are approximately 0.15 mm, and the center-to-center distance D is approximately 0.08 mm. Note that the center-to-center distance D may be the center-to-center distance between the nozzles when the plurality of nozzles 11n are projected from the second direction onto a virtual straight line extending in the first direction, or It may be the distance between the centers of nozzles in a nozzle row consisting of a plurality of nozzles 11n arranged in .

Slanted surfaces 512y and 513y are formed on the housing member 512 and the cover 513, respectively, along the gaps Sa and Sb (see FIG. 4). The inclined surface 512y is connected to the surface 512a, and the inclined surface 513y is connected to the surface 513a. The inclined surfaces 512y and 513y have shapes that approach the surface 512c (that is, move downward) as they approach the gaps Sa and Sb, respectively.

The hook 513f has a portion that overlaps the gap Sa in the vertical direction and defines the bottom surface of the gap Sa. Further, the hook 513f does not overlap the discharge hole 519 in the vertical direction.

The housing member 512 and the cover 513 are electrically connected to each other by contacting each other, and are also electrically connected to the voltage application circuit 61 and the voltage detection circuit 62. The voltage application circuit 61 corresponds to the "voltage application section" of the present invention, and the voltage detection circuit 62 corresponds to the "signal output section" of the present invention.

The voltage application circuit 61 applies a predetermined voltage Va (see FIG. 7) to the housing member 512 and the cover 513 under the control of the control device 9. On the other hand, the channel unit 11 of the head 1 is electrically conductive (for example, made of a metal material) and is held at ground potential. This creates a potential difference between the head 1, the housing member 512, and the cover 513.

The voltage detection circuit 62 outputs a signal indicating the voltage of the housing member 512 and the cover 513 (that is, the potential difference between the head 1 and the housing member 512 and the cover 513) to the control device 9.

As shown in FIG. 6, the control device 9 is an ASIC (Application Specific Integrated Circuit) including a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, and various control circuits. It has 94. The control device 9 is connected to an external device such as a PC for data communication.

The ROM 92 stores programs and data for the CPU 91 to control various operations. The RAM 93 temporarily stores data used when the CPU 91 executes the above program. The CPU 91 issues instructions to the ASIC 94 in accordance with programs and data stored in the ROM 92 and RAM 93 based on recording instructions and the like input from an external device. The CPU 91 and ASIC 94 correspond to the "control unit".

The ASIC 94 is connected to the driver IC 15, the carriage motor 25, the transport motor 45, the cap lift motor 55, the suction pump 56, the voltage application circuit 61, and the voltage detection circuit 62.

During recording, the ASIC 94 drives the driver IC 15, carriage motor 25, and transport motor 45 in accordance with commands from the CPU 91, and performs a "transport operation" that transports the paper P in the transport direction and moves the carriage 2 in the scanning direction. "ejection operation" in which ink is ejected from the nozzle 11n is alternately performed. That is, during recording, the paper P is conveyed intermittently. By repeating the above operations alternately, ink dots are formed on the paper P and an image is recorded.

During maintenance, the ASIC 94 drives the carriage motor 25 to place the head 1 at the maintenance position, and drives the cap lift motor 55 to move the cap device 51 upward in accordance with a command from the CPU 91. As a result, the tip of the side portion 511b of the cap 511 comes into contact with the nozzle surface 11a, and the nozzle surface 11a is covered by the cap 511.

When the suction pump 56 is driven with the nozzle surface 11a covered by the cap 511, a negative pressure is created in the cap 511, and ink is forcibly discharged from the nozzle 11n, and the ink enters the cap 511. Accepted (suction purge). The ink is received on the surface 512a of the housing member 512 and the surface 513a of the cover 513, and is also received in the gaps Sa and Sb.

The ink I discharged toward the gap Sa is held by the hook 513f, as shown in FIG. The surface Ia of the ink I is located below the surface 512a of the housing member 512 and the surface 513a of the cover 513 due to capillary action.

The ink received in the cap 511 as described above passes through grooves (not shown) formed on the side and bottom surfaces of the storage member 512, reaches the discharge hole 519, and passes through the suction pump 56 to the waste liquid tank 57 ( (see Figure 1). However, the ink I received in the gap Sa (see FIG. 5) remains held in the gap Sa.

When inspecting nozzle clogging ("nozzle discharge state" according to the present invention), the ASIC 94 drives the carriage motor 25 to place the head 1 at the maintenance position and drives the driver IC 15 in accordance with a command from the CPU 91. Then, ink is ejected from the plurality of nozzles 11n of the head 1 toward the housing member 512 in the cap 511 and the cover 513.

In this embodiment, a positive voltage Va is applied by the voltage application circuit 61 to the housing member 512 and the cover 513, which function as electrodes for inspection. The ink is positively charged. From the time when the ink is ejected from the nozzle 11n until it lands on the housing member 512 and the cover 513, the voltages of the housing member 512 and the cover 513 increase and reach a voltage Vb higher than the voltage Va (see FIG. 7(a)). . After the ink lands on the storage member 512 and the cover 513, the voltages of the storage member 512 and the cover 513 gradually decrease and return to the voltage Va. On the other hand, when ink is not ejected from the nozzle 11n, the voltages of the housing member 512 and the cover 513 hardly change from the voltage Va (see FIG. 7(b)).

The ink I (see FIG. 5) held in the gap Sa also functions as an electrode for inspection. In other words, the positive voltage Va is applied to the ink I held in the gap Sa by the voltage application circuit 61 as well as to the storage member 512 and the cover 513. Therefore, when ink is ejected toward the gap Sa during inspection, a voltage change similar to that described above occurs.

The ASIC 94 tests for nozzle clogging based on the signal output from the voltage detection circuit 62 (that is, the signal indicating the voltage of the housing member 512 and the cover 513). Specifically, when the voltages of the housing member 512 and the cover 513 exceed the threshold values Vt and Vt', the ASIC 94 determines that the nozzle 11n is not clogged (that is, there is no abnormality in the discharge state of the nozzle 11n). This inspection is performed for each nozzle 11n.

The ASIC 94 performs appropriate processing based on the inspection results. For example, if one or more of the plurality of nozzles 11n is determined to be clogged (that is, there is an abnormality in the ejection state), a suction purge (the suction pump 56 is driven to remove ink from the nozzle 11n). Execute the forced ejection process). If there is no nozzle 11n that is determined to be clogged (that is, there is an abnormality in the ejection state) among the plurality of nozzles 11n, the suction purge is not executed, and the recording process based on the recording command (the above-mentioned "conveyance operation") is performed. and "discharge operation" are performed alternately). Alternatively, among the plurality of nozzles 11n, some of the nozzles 11n that are determined to be clogged (that is, there is an abnormality in the ejection state) are flushed (by driving the driver IC 15, ink is ejected from the nozzles 11n). processing) may be executed.

The ROM 92 stores threshold values Vt and Vt' for each nozzle 11n. The threshold values Vt and Vt' are values higher than the voltage Va and lower than the voltage Vb. Furthermore, among the plurality of nozzles 11n, the threshold value Vt' for a specific nozzle that ejects ink toward the gap Sa during inspection is lower than the threshold value Vt for nozzles other than the specific nozzle.

The specific nozzle is composed of one or more nozzles 11n. For example, considering the assembly accuracy and looseness of the head 1 and the cap device 51, a plurality of nozzles 11n are identified as nozzles that may face the gap Sa in the vertical direction when the head 1 is placed in the maintenance position. You may do so.

As described above, according to the present embodiment, the conductive cover 513 is provided, which covers the convex portion 514p and has the surface 513a along the surface 512a of the housing member 512 on the nozzle surface 11a side ( (See Figure 4). In this case, in the inspection of the ejection state, ink ejected from the nozzle 11n lands on the surface 512a of the storage member 512 and the surface 513a of the cover 513. Then, the discharge state can be inspected based on the voltages of the housing member 512 and the cover 513, which function as inspection electrodes. Therefore, it is possible to suppress the problem that the inspection accuracy of the discharge state deteriorates due to the convex portion 514p.

The cover 513 fits into the recess 512b of the housing member 512 (see FIGS. 3 and 4). In this case, ink can be ejected from the nozzle 11n toward the surface 513a of the cover 513 and the surface 512a located outside the recess 512b of the housing member 512, and the ejection state can be inspected.

There are gaps Sa and Sb between the surface 512a of the housing member 512 and the surface 513a of the cover 513 (see FIGS. 3 and 4). In this case, the cover 513 can be easily attached. Furthermore, as shown in FIG. 5, the ink I can be held in the gap Sa and can be made to function as an electrode for inspection. Furthermore, by holding the ink I in the gap Sa, it is effective to prevent the nozzle 11n covered with the cap 511 from drying out.

The width Wa of the gap Sa is larger than the distance D between the centers of the nozzles 11n (see FIG. 4). In this case, at least one nozzle 11n can be opposed to the gap Sa during the inspection. Then, for the nozzle 11n, the ink I held in the gap Sa functions as an electrode for testing, and testing can be performed.

Slanted surfaces 512y and 513y (surfaces shaped so that they approach the surface 512c as they approach the gap Sa) are connected to at least one of the surface 512a of the housing member 512 and the surface 513a of the cover 513 (FIGS. 4 and 5). reference). Without the inclined surfaces 512y and 513y, the surface Ia of the ink I held in the gap Sa would be located below the surface 512a of the storage member 512 and the surface 513a of the cover 513, as shown in FIG. Both the cases of being located above the surface 512a of the housing member 512 and the surface 513a of the cover 513 (that is, approaching the nozzle surface 11a) can occur with similar probability. In this regard, in this configuration, since the inclined surfaces 512y and 513y exist, the surface Ia of the ink I held in the gap Sa is higher than the surface 512a of the storage member 512 and the surface 513a of the cover 513, as shown in FIG. We can guarantee that it will be located at the bottom. Thereby, the ink I held in the gap Sa functions as an electrode for inspection, and inspection can be performed stably.

Slanted surfaces 512y and 513y are connected to the surface 512a of the housing member 512 and the surface 513a of the cover 513, respectively (see FIGS. 4 and 5). In this case, it can be more reliably guaranteed that the surface Ia of the ink I held in the gap Sa is located below the surface 512a of the storage member 512 and the surface 513a of the cover 513. Thereby, the ink I held in the gap Sa functions as an electrode for inspection, and inspection can be performed more stably.

The hook 513f provided on the cover 513 has a portion that overlaps the gap Sa in the vertical direction and defines the bottom surface of the gap Sa (see FIGS. 4 and 5). In this case, the hook 513f serves as an ink receiving part, making it easy to hold the ink in the gap Sa.

The cover 513 is long in the first direction and is more easily deformed by a force in the first direction than by a force in the second direction. In the cover 513, hooks 513f are provided at both ends in the first direction where the cover 513 is easily deformed (see FIG. 3). In this case, the cover 513 can be easily attached.

The hook 513f does not overlap the discharge hole 519 in the vertical direction (see FIGS. 3 and 4). In this case, when suction force is generated in the cap 511 through the discharge hole 519, the suction force is not concentrated on the hook 513f and acts on the ink I (see FIG. 5) held by the hook 513f. The suction force can be suppressed.

The housing member 512 is made of conductive resin and covers the discharge hole 519 (see FIG. 4). In this case, when a suction force is generated in the cap 511 through the discharge hole 519, the housing member 512 acts as a resistance, and it is possible to suppress the suction force from being generated intensively in the discharge hole 519. In other words, the suction force can be distributed throughout the cap 511. Thereby, ink can be uniformly sucked from the nozzle 11n over the entire cap 511.

The housing member 512 and the cover 513 are electrically connected to the voltage application circuit 61 (see FIG. 4). In this case, inspection can be performed by applying a predetermined voltage Va (see FIG. 7) to the housing member 512 and the cover 513.

When the housing member 512 and the cover 513 face the nozzle surface 11a, the vertical distance G between the nozzle surface 11a and the surface 512a and the vertical distance G between the nozzle surface 11a and the surface 513a are the same. Yes (see Figure 4). In this case, inspection accuracy can be improved.

When the voltages of the housing member 512 and the cover 513 exceed the threshold values Vt and Vt', the ASIC 94 determines that the nozzle 11n is not clogged (that is, there is no abnormality in the discharge state of the nozzle 11n). Among the plurality of nozzles 11n, the threshold value Vt' for a specific nozzle that ejects ink toward the gap Sa during inspection is lower than the threshold value Vt for nozzles other than the specific nozzle (see FIG. 7). The ink I held in the gap Sa functions as an electrode for inspection together with the storage member 512 and the cover 513, but the surface Ia of the ink I is located below the surface 512a of the storage member 512 and the surface 513a of the cover 513. (See Figure 5). Therefore, the maximum voltage value Vb when ink is ejected toward the surface Ia (see FIG. 7(a)) is higher than the maximum voltage value Vb when ink is ejected toward the surfaces 512a and 513a. , becomes lower. Therefore, in this embodiment, the threshold value Vt' for a specific nozzle that discharges ink toward the gap Sa is set lower than the threshold value Vt for a nozzle that discharges ink toward a portion other than the gap Sa. Thereby, appropriate test results can be obtained.

<Another embodiment>
Next, another embodiment of the present invention will be described.

In the embodiment described above (see FIG. 7), the voltage application circuit 61 applies a positive voltage Va to the housing member 512 and the cover 513. In contrast, in this embodiment (see FIG. 8), the voltage application circuit 61 applies a negative voltage Va to the housing member 512 and the cover 513.

In the present embodiment (see FIG. 8), the voltages of the storage member 512 and the cover 513 decrease from the time the ink is ejected from the nozzle 11n until it lands on the storage member 512 and the cover 513, and the voltage Vb is lower than the voltage Va. (See FIG. 8(a)). After the ink lands on the storage member 512 and the cover 513, the voltages of the storage member 512 and the cover 513 gradually increase and return to the voltage Va. On the other hand, when ink is not ejected from the nozzle 11n, the voltages of the housing member 512 and the cover 513 hardly change from the voltage Va (see FIG. 8(b)).

Similarly to the storage member 512 and the cover 513, a negative voltage Va is applied to the ink I held in the gap Sa by the voltage application circuit 61. Therefore, when ink is ejected toward the gap Sa during inspection, a voltage change similar to that described above occurs.

In the embodiment described above (see FIG. 7), the ASIC 94 determines that the nozzle 11n is not clogged (that is, there is an abnormality in the discharge state of the nozzle 11n) when the voltages of the housing member 512 and the cover 513 exceed the threshold values Vt and Vt'. It is determined that there is no On the other hand, in the present embodiment (see FIG. 8), the ASIC 94 determines that the nozzle 11n is not clogged (that is, the discharge state of the nozzle 11n is It is determined that there is no abnormality in the

In the present embodiment (see FIG. 8), among the plurality of nozzles 11n, the threshold value Vt' for a specific nozzle that ejects ink toward the gap Sa during inspection is lower than the threshold value Vt for nozzles other than the specific nozzle. expensive. The ink I held in the gap Sa functions as an electrode for inspection together with the storage member 512 and the cover 513, but the surface Ia of the ink I is located below the surface 512a of the storage member 512 and the surface 513a of the cover 513. (See Figure 5). Therefore, the lowest voltage value Vb (see FIG. 8(a)) when the ink is discharged toward the surface Ia is lower than the lowest voltage value Vb when the ink is discharged toward the surfaces 512a and 513a. , becomes higher. Therefore, in this embodiment, the threshold value Vt' for a specific nozzle that discharges ink toward the gap Sa is set higher than the threshold value Vt for a nozzle that discharges ink toward a portion other than the gap Sa. Thereby, appropriate test results can be obtained.

<Modified example>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made within the scope of the claims.

The inspection of "nozzle ejection state" is not limited to the inspection of "nozzle clogging", but may also be the inspection of "ink flying direction" or "ejection amount". Further, the processing performed based on the test results is not limited to "suction purge" and "flushing", and various processing may be performed.

When discharging the liquid from the nozzle toward the housing member and the cover during inspection, the present invention is not limited to driving the driver IC, and a suction pump may be driven.

In the embodiment described above, the voltage detection circuit 62 outputs a signal indicating the voltage of the housing member 512 and the cover 513 to the control device 9, and the control device 9 outputs a signal indicating the voltage of the housing member 512 and the cover 513 based on the signal. and the threshold values Vt and Vt', but the comparison is not limited thereto. For example, the voltage detection circuit 62 compares the voltage of the housing member 512 and the cover 513 with the threshold values Vt and Vt', and processes a signal corresponding to the result (i.e., a signal indicating the voltage of the housing member 512 and the cover 513). signal) may be output to the control device 9.

During testing, the housing member and cover may be held at ground potential and a positive or negative voltage may be applied to the head. In this case, the housing member and the cover may not be electrically connected to the voltage application section, and the head may be electrically connected to the voltage application section. Further, in this case, the head may be electrically connected to a voltage detection circuit (signal output section), and inspection may be performed based on the voltage of the head.

As long as the liquid ejected from the nozzle creates a potential difference between the head, the accommodation member, and the cover during the inspection, the liquid ejected from the nozzle is not limited to landing on the accommodation member and the cover. For example, during the inspection, the liquid ejected from the nozzle may not land on the housing member and the cover, and an induced current may be generated in the housing member and the cover.

The present invention is not limited to creating a potential difference between the head, the housing member, and the cover in advance during the inspection. The liquid discharged from the nozzle becomes slightly positively charged when it leaves the nozzle surface. The voltage of the housing member and the cover increases from when this charged liquid is discharged from the nozzle until it lands on the housing member and the cover. Inspection can be performed based on this voltage change.

The CPU and ASIC are not limited to sharing the functions of the control unit. For example, only a CPU or only an ASIC may function as the control section, or a plurality of CPUs and/or a plurality of ASICs may share the function of the control section.

A "surface shaped so that the closer it gets to the gap, the closer it gets to the bottom surface" may be connected to only one of the surface of the housing member (another surface) and the surface of the cover.

"The surface whose shape approaches the bottom as it approaches the gap" is not limited to the non-curved inclined surfaces 512y and 513y as in the above-described embodiment, but may be a curved surface.

The housing member may be fixed to the cap by caulking the tip of the convex portion without providing a retaining ring. Alternatively, the housing member 2512 may be fixed to the cap by fitting the housing member 2512 into the recess 514x at the tip of the convex portion 514p, as in the modification shown in FIG.

In the embodiment described above (see FIG. 4), the housing member 512 is fixed to the cap 511 by the convex portion 514p of the cap holder 514, but the present invention is not limited thereto. For example, the cap holder 514 may be omitted, a convex portion passing through the housing member 512 may be provided on the bottom portion 511a of the cap 511, and the housing member 512 may be fixed to the cap 511 by the convex portion.

Although the hooks extend outwardly from the sidewalls of the cover in the embodiments described above (see FIG. 4), they may extend inwardly from the sidewalls of the cover. In this case, the recess of the receiving member may be provided inside the side wall of the cover.

The cover is not limited to fitting into the recess of the housing member. For example, in the above-described embodiment, even if the portion of the housing member outside the cover is omitted and the cover is directly attached to the cap (for example, the hook of the cover is caught in a recess provided in the cap). good. Specifically, for example, in the cap device 251 according to the modified example of FIG. 9, no recess is formed in the surface 2512a of the housing member 2512, and the cover 2513 is directly attached to the cap 511. The housing member 2512 fits into a recess 514x formed at the tip of the protrusion 514p of the cap holder 514. The cover 2512 covers the convex portion 514p and has a surface 2513a along a surface 2512a of the housing member 2512 on the nozzle surface side. The housing member 2512 covers the discharge hole 519.

Grooves may be provided on the surface of the housing member (another surface on the nozzle side) or the surface of the cover from the viewpoint of improving the drainage of liquid that has landed on the surface.

The housing member is not limited to being made of conductive resin, but may be made of a porous material (absorbent material) such as sponge.

The liquid ejected from the nozzle is not limited to ink, and may be any liquid (for example, a treatment liquid that aggregates or precipitates components in the ink, a liquid in which metal particles are dispersed in a solvent, etc.).

The liquid ejection head is not limited to a serial type, but may be a line type (that is, a type in which liquid is ejected onto a medium in a fixed position).

The actuator is not limited to a piezo type actuator using a piezoelectric element, and may be of other types (for example, a thermal type using a heating element, an electrostatic type using an electrostatic force, etc.).

The medium to be ejected is not limited to paper, and may be, for example, cloth, an electronic board (base material for a flexible printed circuit board, etc.), a sheet for outdoor advertising, cardboard, a resin case for a terminal such as a smartphone, or the like.

The present invention is not limited to printers, but can also be applied to facsimiles, copy machines, multifunction devices, and the like.

1 head (liquid ejection head)
11n nozzle 11a nozzle surface 51 cap device 511 cap 512 housing member 512a surface (another surface on the nozzle surface side)
512b Recess 512c Surface (surface on nozzle side, bottom of recess)
512d Hollow 512y Inclined surface 513 Cover 513a Surface 513f Hook 513y Inclined surface 514 Cap holder 514p Convex part (fixed part)
515 Retaining ring (fixed part)
519 Discharge hole 61 Voltage application circuit (voltage application section)
62 Voltage detection circuit (signal output section)
91 CPU (control unit)
94 ASIC (control unit)
100 Printer (liquid ejection device)
251 Cap device 2512 Housing member 2512a Surface (surface on nozzle surface side)
2513 Cover 2513a Surface P Paper (medium to be ejected)
Sa Gap Wa Width D Center-to-center distance Vt, Vt' Threshold

Claims (15)

a cap for covering a nozzle surface of a liquid ejection head having a nozzle surface on which a plurality of nozzles are formed for ejecting liquid onto a medium to be ejected;
a conductive housing member housed in the cap so as to be able to face the nozzle surface, and capable of generating a potential difference between the housing member and the liquid ejection head;
a convex portion extending through the housing member so as to protrude from a surface of the housing member on the nozzle surface side when the housing member and the nozzle face face each other, and fixing the housing member to the cap; A fixed part that
a conductive cover that covers the convex portion and has a surface along the nozzle surface side of the housing member, and is capable of generating a potential difference with the liquid ejection head;
A cap device comprising: The housing member has a recess whose bottom surface is a surface on the nozzle surface side,
The cap device according to claim 1, wherein the cover fits into the recess. 3. The cap device according to claim 2, wherein there is a gap between another surface of the housing member on the nozzle surface side located outside the recess and the surface of the cover. The gap extends in a predetermined direction along the bottom surface,
The cap device according to claim 3, wherein a width of the gap in an orthogonal direction perpendicular to the predetermined direction and along the bottom surface is larger than a center-to-center distance of the plurality of nozzles in the orthogonal direction. . According to claim 3 or 4, a surface having a shape that approaches the bottom surface as it approaches the gap is connected to at least one of the other surface of the housing member and the surface of the cover. cap device. 6. The cap device according to claim 5, wherein the other surface of the housing member and the surface of the cover are each connected to a surface having a shape that approaches the bottom surface as it approaches the gap. . The housing member has a recess that communicates with the recess and extends in a first direction along the bottom surface,
the cover has a hook inserted into the recess;
The cap device according to any one of claims 3 to 6, wherein the hook includes a portion that overlaps the gap in a direction perpendicular to the bottom surface and defines a bottom surface of the gap. The length of the cover in the first direction is longer than the length in a second direction perpendicular to the first direction and along the bottom surface,
8. The cap device according to claim 7, wherein the hooks are provided at both ends of the cover in the first direction. The cap device according to claim 7 or 8, wherein the hook does not overlap, in a direction perpendicular to the bottom surface, a discharge hole formed at the bottom of the cap for discharging the liquid in the cap. . 10. The housing member is made of conductive resin and covers a discharge hole formed at the bottom of the cap for discharging the liquid in the cap. Cap device described in. The cap device according to any one of claims 1 to 10, wherein the housing member and the cover are electrically connected to a voltage application unit that applies a voltage to the housing member and the cover. a liquid ejection head having a nozzle surface on which a plurality of nozzles are formed for ejecting liquid onto a medium to be ejected;
a cap for covering the nozzle surface;
a conductive housing member housed in the cap so as to be able to face the nozzle surface, and capable of generating a potential difference between the housing member and the liquid ejection head;
a convex portion extending through the housing member so as to protrude from a surface of the housing member on the nozzle surface side when the housing member and the nozzle face face each other, and fixing the housing member to the cap; A fixed part that
a conductive cover that covers the convex portion and has a surface along the nozzle surface side of the housing member, and is capable of generating a potential difference with the liquid ejection head;
a signal output unit that outputs a signal indicating a potential difference between the liquid ejection head, the housing member, and the cover;
comprising a control unit;
The control unit may cause the plurality of nozzles to eject liquid toward the housing member and the cover, and inspect the ejection state of the plurality of nozzles based on the signal output from the signal output unit. A liquid ejection device characterized by: When the accommodating member and the cover face the nozzle surface, the distance between the nozzle surface and the surface of the accommodating member in a direction perpendicular to the nozzle surface, and the distance between the nozzle surface and the surface of the cover 13. The liquid ejecting device according to claim 12, wherein the distances are the same. The housing member has a recess whose bottom surface is a surface on the nozzle surface side,
The cover fits into the recess,
There is a gap between another surface of the housing member on the nozzle surface side located outside the recess and the surface of the cover,
A surface having a shape that approaches the bottom surface as it approaches the gap is connected to at least one of the other surface of the housing member and the surface of the cover;
When performing the inspection, the control unit determines that there is no abnormality in the discharge state of the nozzle when the potential difference indicated by the signal exceeds a threshold;
12. The threshold value for a specific nozzle that discharges liquid toward the gap during the inspection among the plurality of nozzles is lower than the threshold value for nozzles other than the specific nozzle. or 13. The liquid ejection device according to 13. The housing member has a recess whose bottom surface is a surface on the nozzle surface side,
The cover fits into the recess,
There is a gap between another surface of the housing member on the nozzle surface side located outside the recess and the surface of the cover,
A surface having a shape that approaches the bottom surface as it approaches the gap is connected to at least one of the other surface of the housing member and the surface of the cover;
When performing the inspection, the control unit determines that there is no abnormality in the discharge state of the nozzle when the potential difference indicated by the signal is below a threshold;
12. The threshold value for a specific nozzle that discharges liquid toward the gap during the inspection among the plurality of nozzles is higher than the threshold value for nozzles other than the specific nozzle. or 13. The liquid ejection device according to 13.

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